Explosive actuated valve



Feb. 25, 1964 E, sgEBEL ETAL, 3,122,154

EXPLOSVE ACTUTED VALVE Filed Jan. 9, 1961 By Jayme/mamy l 26 M55/'agiUnited States @atene Q 3,122,154 EXPLOSIVE ACTUATED VALVE John E.Siebel, 3525 Alsace Ave., Los Angeles, Calif., John R. Mooney, LosAngeles, Calif.; said Mooney assignor to said Siebel FiledJan. 9, 1961,Ser. No. 81,293 11 Claims. (Cl. 137-68) This invention relates tovalving devices and more particulanly to so-called explosively actuatedvalves adapted to control highly fugitive fluids such as hydrogen orhelium under pressures in the order of several thousand pounds persquare inch.

Heretofore, valves of the before mentioned kind usually have been eitherof two single-operation types, namely,

either a normally closed valve which may be opened to permit the ow ofuid therethrough, or a normally open valve which may be closed toprevent the ilow of fluid therethrough. It is well known to employexplosives or combustible propellant materials for actuation of suchvalves, and such valves have heretofore usually relied upon therupturing or perforating of a diaphragm barrier or the like member toeffect the opening of the valve, or on the other hand, the driving of aplug or the like element into an opening to shut olf the ow of uid. Suchvalves, in the case of the normally closed, openable types usually havehad the disadvantage of jeopardizing the cleanliness of the uid systemsin which they .were connected; and in the case of the normally open,closeable types, they had the danger of not always succeedingineffecting a perfect shut-off. With both of the foregoing types ofvalves, unbalanced forces, resulting from both the static pressures anddynamic forces of the fluids to be controlled and from the residualpressure of the activating uids or gases, tended to move the Avalveelements to undesired positions, particularly where such valves wereused under conditions of severe vibration.

Such valves heretofore employed also often had valving elements, thefunctional surfaces of which were subject to deterioration both as toshelf and service life, with the result that they could not be reliedupon to function satisfactorily at all times and over long periods oftime of either inactivity or service with the kinds of uids and underthe conditions for which the valves of the present invention areespecially intended.

It is accordingly an object of the present invention to provide a valvewhich is capable of controlling highly fugitive uids under extremelyhigh pressures, without leakage.

Another object of this invention is to provide such a valve which may beeither singly or doubly operated by Ymeans of explosive or combustiblegas-generating materials.

A still further object of this invention is to provide such a valvewhich neither in its static state nor in any of its operational cycles,jeopardizes the cleanliness of the uid system in which it is connected.

It is another object of this invention to provide a valve having a highdegree of reliability in fulfilling the vforegoing objects at any timeor after long periods of in opened condition or in closed condition arebalanced both as to the pressures and dynamic forces of the fluids to bevalved and the residual pressures of propulsive fluids or gases by whichit is actuated, so that there is no force tending either to open orclose the valve at any time other than at the instant of its intendedactuation.

It is a still further object of this invention to provide a valve of thebeforementioned kind in which there is at no time, either in its openedcondition or in its closed condition, any opposition to the movement ofthe operative parts of the valve, either by reason of the pressure ofthe uid in, or the ow of the fluid through the valve, and in which theonly forces necessary to be overcome by the actuating means are thefrictional forces of the moving parts of the valve.

The objects of this invention, broadly considered, are accomplished inbrief, by employing a valve structure in which the valving elements andthe bore of the valve housing in which the elements are positioned andmove to perform the function of opening or closing the fluid orwpassages therethrough, are of such relative sizes and shapes as to be insubstantial dimensional interference with one another, or in otherwords, such as to make interference fits with one another, such that atthe interfaces or areas of contact therebetween, the metals thereof arein extremely high-compressive, intimate contact, so much so that uponmovement of the valve elements within the valve bore, deformation of themetals occurs at the areas of mutual contact. This deformation isfundamentally elastic with possibly a slight amount of permanentdeformation or flow. This insures that at all times a perfectmetal-to-metal seal will be maintained.

These and other objects, advantages and features of novelty of thisinvention will be evident hereinafter.

In the drawings which illustrate preferred embodiments of the inventionand in which like reference characters designate the same or similarparts throughout the several views:

FIGURE l is a longitudinal sectional view of the body of a valveembodying the present invention and showing a normally or initially openversion thereof before actuation to its closed position;

FIGURE 2 is a longitudinal sectional view of the valve of FIGURE 1, butshowing the valve after having been actuated to its closed position; and

FIGURE 3 is a fragmentary longitudinal sectional view of a modificationof the apparatus of FIGURES l and 2.

The apparatus of the invention is as follows:

Referring rst primarily to FIGURE l, the housing or body portion of thevalve is shown at 10, such body portion being formed with laterallydirected, longitudinally offset inlet and outlet ducts or openings 12and 14 which are threaded at their outer end portions as shown at 15 and16 to receive suitable connections with tubing or piping which maycomprise a high pressure uid system in which the valve is to beconnected. The valve body 10 is also provided with a longitudinal valvebore 17 of uniform inside diameter except for intermediate, undercutsections 18 and 20, with which the connection openings 12 and 14communicate through junction ports 19 and 21, respectively. The oppositeends of the bore 17 terminate in counterbored, internally threaded ends2S and 29. The valve bore 17, in one version of the apparatus as shownin FIGURES l and 2, closed at one end by an externally threaded plug 22,and at the other end by an externally threaded, electrically actuated,gas pressure generating unit 24. ring seals are provided in annularrecesses at the outer ends of the threaded portions of the plug 22 andthe gas pressure generating unit 24. as shown at 11 and 13,respectively.

The gas pressure generating unit 24 may be of several different kindsadapted to supply gas under pressure for operation of the valve, but inthe preferred form herein illustrated it is provided with an inwardlyextending initially closed cartridge portion 25 composed of a hollow,metal sleeve 26, which is normally closed at its outer end by arelatively thick transverse wall 43 and its inner end by a relativelythin detachable metal diaphragm 30 sealed, fluid tight, around itsperiphery to the inner end of the walls of sleeve 26 by suitable meanssuch as by soldering, as shown at 31. The cavity, thus formed within theclosed cartridge portion 25, contains a suitable quantity of acombustible material or explosive. gas-forming material. for example, apropellant such as gun powder.

The exterior part of the gas pressure generating unit 24 takes the formof an integral, electrical connector receptacle, which is formed with anoutwardly extending cylindrical shell 32, threaded on the exteriorthereof, as shown at 33, to receive a threaded connector retainer ring`and forming a cylindrical recess 34 on the interior thereof adapted toreceive a conventional electrical connector plug.v l

A- pair of separate electrical contact pins 36 and 37 extend axiallyoutward within the receptacle recess 34 from the receptacle wall betweenthe recess 34 and the cartridge portion 25, and are adapted to plug intotubular terminal members of the previously mentioned electricalconnector plug. The electrical contact pins 36 and 37, extend throughthe receptacle wall 43 into the interior of the cartridge portion 25through insulating bushings, as shown at 38 and 39. Such insulatingbushings 38 and 39 may be made of glass, plastic or other suitableinsulating materials as well known in the art, capable of withstandingthe temperatures and gas pressures generated within the cartridgeportion 25 upon ignition of the combustible material therein. By w'ay ofexample of a suitable connector receptacle and assembly configurationwhich may be made integral with the gas pressure generating unit, asbefore described, is the type designated as United States MilitaryStandard Drawing M.S. 33678, Style P.

A relatively fine, fusible igniter wire 40 extends between soldering lugportions 41 and 42 of the ends of the connector pins 36 and 37, whichextend into the cartridge portion 25. Further detailed description ofthe pressure generating means including the cartridge portion 25thereof, is not herein given, since devices of this kind suitable foruse in connection with the valve of this invention are well known.

Referring again primarily to FIGURE l, the valve bore 17 of the valvebody 10 contains a valve spool 45 formed with threevcoaxial,longitudinally spaced-apart, generally disc-shaped valve elements 46, 47and 48, centrally interconnected by integral stem portions of reducedoutside diameter, as shown at 49 and 50. Each of the valve elements isformed with a longitudinally curved peripheral surface, preferablyhaving or approximating the geometrical shape of a coaxial, equatorial,spherical or spheroidal zone. Such surfaces preferably have polishedfinishes and are of such maximum outside diameters as to makeinterference fits with the inside surface of the valve bore 17. Aninterference tit of 0.0012" i .0002" between the maximum outsidediameter of the approximately spherical or spheroidal surface of thevalve elements and the inside diameter of the valve bore 17 has beenfound suitable in effecting the desired uid seal, where the materialsuse for the valve body and the valve elements are alloy steels oraluminum alloys. Such materials may be used separately or in combinationfor both valve elements and valve body. but preferably the valveelements and the material of the inside surface of the valve bore are ofthe same material to minimize galvanic corrosion effects therebetween.stainless steel has been found to be satisfactory in most applicationsof the valve.

The valve spool 45 is provided with a passage 5l, shown in dotted lines,of somewhat restricted cross section, extending coaxially therethroughfrom end-to-end, such passage being for the purpose of pressureequalization between the opposite ends of the valve bore 17, as willhereinafter be more fully explained in connection with the operation ofthe valve.

FIGURE 3 illustrates a modification of the apparatus of FIGURES 1 and 2wherein, instead of-the plug 22 closing one end of the valve bore 17, agas pressure generating unit 24a. including a cartridge portion 25asimilar or identical to that of the unit 24, is substituted therefor. Aplug similar to that shown at 22 may be employed in place of thepressure generating unit 24 where it is desired to operate the valvefrom an initially closed' to an opened condition instead of from aninitially open to a closed condition. However, the gas pressuregenerating unit 24a may be used in addition to that at 24 where it isdesired to effect a double operation of the valve, namely, either from anormally open to a closed condition and return to an open condition. orfrom a normally closed to an open condition and return to a closedcondition.

The operation of the apparatus is as follows:

In an initial, unactuated condition of the valve, as shown in FIGURE l,the valve spool 4S is located in4 its extreme left-hand position in thevalve bore, at which location the valve element 46 of the valve spool islocated adjacent the inner end of the propellant cartridge portion 25,and the other two valve elements 47 and 48 of the valve spool arelocated in spaced-apart positions bridging or straddling both of theinlet and outlet duct ports 19 and 21 at their points of juncture withthe valve bore 17, and also straddling the intermediate section 23 ofthe valve bore extending therebetween. In this initial position of thevalve spool, fluid may obviously flow freely through the valve in eitherdirection -between the inlet and outlet ducts 12 and 14.

To actuate the valve, a suitable current source is connected to theconductor pins 36 and 37 through a suitable connector,as'beforementioned, whereby the igniter lament 40 is fused. therebyigniting the combustible propellant material within the cartridgeportion 25 of the pressure generating unit 24, with the result that thesealing diaphragm 30 of thc cartridge is detached therefrom and theresultant generated gas pressure acting against it and against theadjacent face of the valve element 46 forces the valve spool to movethrough the bore 17 to its righthandmost position, shown in FIGURE 2.Following this action, the pressures in the opposite ends of the borewill be gradually equalized by leakage of the higher pressure actuatinggases in the left-hand end of the valve bore past the diaphragm 30 andthrough the pressure-equalization duct 51 to the right-hand end of thevalve bore, whereupon due to the interference tit between the peripheryof the valve elements and the inside surface of the valve bore, thevalve spool 45 will be secured against subsequent axial movement, unlesssubsequently otherwise actuated as hereinafter described.

In this latter right-hand position of the valve spool 45 in the valvebore, following the beforementioned actuation thereof, the valve element47 is positioned intermediate the duct ports 19 and 2l, as shown at 35,thereby separating them from communication with one another and therebycutting off communication between the inlet and outlet openings 12 and14. In view of the fact that at this latter position of the valve spoolthe valve' elements 46 and 47 straddle the port 19 and valve elements 47and 48 straddle the valve port 21, all pressures and forces Corrosionresistant or so-called.

communicated to the valve spool thrown either of the openings 12 or 14are statically balanced such that there is no tendency for the valvespool 45 to be moved thereby axially in either direction in the valvebore 1.7. Likewise, in the opened condition of the valve, ashereinbefore described in connection with FIGURE 1, due to thestraddling position of the valve elements 47 and 4S across ports 19 and21, all forces acting upon the valve spool either by reason of thestatic pressure or uid in the valve, or due to any dynamic force of flowof fluid in either direction through the valve, are balanced wherebythere is no tendency for the valve spool to move through the valve borein either direction from its opened position.

In event it is desired to arrange the valve to operate in a manneropposite to that hereinbefore described and shown in connection withFIGURES 1 and 2, that is, with the valve spool initially located in itsright-handmost, valve-closing position as shown in FIGURE 2, and to beactuated to move it to the left-handmost, valve-opening position asshown in FIGURE l, a gas pressure generating unit 24a, the same as oridentical to that of the unit 24, hereinbefore described, may besubstituted for the plug 22 and placed in the right-hand end of thevalve bore, as shown in FIGURE 3. With this substitution andmodiiication, the valve is actuated by means of the unit 24a in the samemanner as hereinbefore described in connection with the actuation of thevalve by the unit 24, and the resultant combustion gases generated inthe right-hand end of the valve bore act upon the end of the valveelement 48 to move the valve spool 45 in a left-hand direction to theposition in the left-hand end of the bore 17, shown in FIGURE l.

An important feature of this valve is its provision for protecting thefluids in the valve at all times from contamination by the products ofcombustion of the gas pressure generating units. This is accomplished bythe presence of the end valve elements 46 and 48 which, subsequent tothe actuation of the valve by tiring the combustible propellant in thecartridge 25, move from the positions shown in FIGURE l to the positionsshown in FIGURE 2, at which either and both positions all of the gaseousproducts of the combustion of the propellant material are retained,sealed off in the ends of the valve bore from communication with the uidto be or being valved within the valve uid passages. Similarly, it is tobe noted that if the valve spool is initially located as shown inFIGURES 2 and 3, in which position ow of fluid through the valve is cutofi, to the position shown in FIGURE l, in which the uid to the valve isfree to pass through the valve, the valve elements 46 and 48 likewise atall times act as barriers to insure freedom of contamination of thevalved uids by any of the contents of the right-hand or left-hand endsof the bore, such as the products of combustion of the pressuregenerating materials of cartridge 25a. Freedom from any possiblecontamination of the fluids in the system in which the valve isconnected is thereby at all times insured. This latter feature of thevalve is also important in connection with the ocpration of the valve asdescribed in connection with the apparatus of FIGURE 3.

Referring now principally to FIGURE 3, another irnportant featureof thisinvention is the fact that propellant units such as shown at 24 and 24amay be initially attached at both ends of the valve bore 17 whereby thevalve may be successively, doubly actuated to move the valve spool 45either from an initial position in which the valve is open to flow offluid therethrough, to a second position in which the valve is closed toow of iiuid therethrough, followed by a second operation which returnsthe valve spool 45 from its shut-off position to the open position; orthe reverse of these sequential operations may obviously be employed.Thus, the valve is capable of at least two successive operations;namely, from an initially open to a closed condition, or from aninitially closed to an open condition, or both of such operations insequence.

It is to be understood that the foregoing is illustrative only and thatthe invention is not limited thereby but may include variousmodifications and changes made by those skilled in the art withoutdistinguishing from the scope of the invention as defined in theappended claims.

What is claimed is:

1. Valve apparatus comprising: a valve body portion having a bore formedtherein; closure means for each end of said bore; separate inlet andoutlet ducts in said body, each communicating at separate longitudinallyspacedapart locations, with said bore, there being an intermediate,uninterrupted section of said bore extending between such spaced-apartlocations; a valve element located coaxially in said bore, said valveelement extending closingly across said bore and having a peripheralsurface portion in slidable sealing engagement with the inside surfaceof the wall of said bore, said valve body portion and said surfaceportion being composed of a material having a hardness and rigidity atleast approximating that of a metal of the class consisting of aluminumand steel, said peripheral surface having the form of a longitudinallyconvexly curved zone and said zone having a maximum outside diametergreater than the inside diameter of said bore, whereby said peripheralsurface makes an interference press fit within said bore, said valveelement being slidable axially within said bore between an axialposition in a section of said bore outside of said intermediate sectionat which said ducts are in communication with each other through saidintermediate section, and an axial position within said intermediatesection at which said ducts are thereby cut oi from communication witheach other, vwhile maintaining said t in said section of said bore; andforce means actuatable for moving said valve element axially in saidbore between said positions.

2. Valve apparatus comprising: a valve body portion having a bore formedtherein; closure means for each end of said bore; separate inlet andoutlet ducts in said body, each communicating at separate longitudinallyspacedapart locations, with said bore, there being an intermediate,uninterrupted section of said bore extending between such spaced apartlocations; a valve element located coaxially in said bore, said valveelement extending closingly across said bore and having a peripheralsurface portion in slidable sealing engagement with the inside surfaceof the Wall of said bore, said valve body portion and said surfaceportion being composed of a material having a hardness and rigidity atleast approximating that of a metal of the class consisting of aluminumand steel, and said peripheral surface having the form of alongitudinally convexly curved zone and having a maximum outsidediameter greater than the inside diameter ofv said bore, whereby saidperipheral surface makes an interference press t within said bore, saidvalve element being slidable axially withinsaid bore between an axialp0- sition in a section of said bore outside of said intermediatesection at which said ducts are in communication with each other throughsaid intermediate section, and an axial position within saidintermediate section at which said ducts are thereby cut ot fromcommunication with each other, while maintaining said tit in saidsections of said bore; and force means contained within an end of saidbore actuatable for moving said valve element axially in said borebetween said positions.

3. Valve apparatus comprising: a valve body portion having a bore formedtherein; closure means for each end of said bore; separate inlet andoutlet ducts in said` body, each communicating at separate,longitudinally spacedapart juncture locations, with said bore, therebeing an intermediate, uninterrupted section of said bore extendingbetween such spaced-apart juncture locationsg'a valve spool located insaid bore, said valve spool being formed with a pair of coaxial, axiallyspaced-apart annular valve elements interconnected by an intermediatestem portion of reduced outside diameter relative to that of said valveelements, each of said valve elements having a peripheral surface ofcontact with the inside surface of the wall of said bore having theshape of a longitudinally convexly curved zone and having a maximumoutside diameter greater than the inside diameter of said bore, wherebysaid surface of contact and the inside surface of said bore make aninterference fit with one another, said valve body portion and saidannular valve elements being composed of a material having a hardnessand rigidity at least approximating that of a metal of the classconsisting ofaluminum and steel, said valve spool being slidable axiallywithin said bore between an axial position at which both said valveelements are in a section of said bore outside said intermediate sectionand said ducts are in communication with yeach other through saidintermediate section of said bore` and an axial position at which saidvalve elements are positioned in sections of said bore on opposite sidesof one of said spaced-apart juncture locations and said inlet and outletducts are thereby cut olf yfrom communication with each other by atleast one of said valve elements, said t being maintained in saidsections of said bore; and means for moving said valve spool betweensaid locations.

4. Valve apparatus in accordance with claim 3 in which said means formoving said valve spool is contained within an end of said bore.

5. Valve apparatus in accordance with claim 4 in which said means formoving said valve spool comprises combustible gas generating material.

6. Valve apparatus comprising: a valve body portion having a bore formedtherein; closure means for each end of said bore; separate inlet andoutlet ducts in said body, each communicating with an intermediateportion of said bore at separate, adjacent, longitudinally spaced-apart,juncture locations, a valve spool located in said bore, said valve spoolhaving rst, second and third coaxial, axially spaced apart, annularvalve elements interconnected by intermediate stem portions of reducedoutside diameter relative to that of said valve elements, each of saidvalve elements having a peripheral surface of contact with the insidesurface of the wall of said bore having a shape at least approximatingthat of a longitudinally convexly curved zone and having a maximumoutside diameter greater than the inside diameter of said bore, wherebysaid surface of contact and the said inside surface of said bore make aninterference fit with one another, said valve body portion and saidannular valve elements being composed of a material having a hardnessand rigidity at least approximating that of a metal of the classconsisting of aluminum and steel, said valve spool being slidableaxially within said bore between an axial position within said bore atwhich a first one of said valve elements is adjacent one end portion ofsaid bore and the second and third ones of said valve elements arelocated in straddling position relative to both said adjacent juncturelocations whereby said inlet and outlet ducts are in communication witheach other through a portion of said bore intermediate said second andthird valve elements, and the end portion of said bore adjacent saidfirst valve element is isolated by said first valve element from both ofsaid ducts, and another position in said,bore at` which one of saidsecond and third valve elements is adjacent the other end of said boreand one of said second and third valve elements is positioned in saidbore intermediate said juncture locations, at which another positionsaid inlet and outlet ducts are thereby cut off from communication witheach other, and the other end portion of said bore adjacent said outerone of said second and third valve elements is isolated from both saidducts; and means'for applying force to said valve spool to move itaxially in said bore between said positions.

7. Valve apparatus comprising: a valve body portion having a bore formedtherein; closure means for each f end of said bore; separate inlet andoutlet ducts in said body, each communicating with an intermediateportion of said bore at separate, adjacent, longitudinally spacedapart,juncture locations, a valve spool located in said bore and slidableaxially therein, said valve spool having first, second and thirdcoaxial, axially spaced-apart, annular valve elements interconnected byintermediate stem portions of reduced outside diameter relative to thatof said valve elements, each of said valve elements having a peripheralsurface of contact with the inside surface of the wall of said borehaving the shape of a longitudinally convexly curved zone and having amaximum outside diameter greater than the inside diameter of said bore,whereby said surface of contact and the inside surface of said boremalte an interference fit with one another, said valve body portion andsaid annular valve elements being composed of a material having a'hardness and rigidity at least approximating that of a metal of theclass consisting of aluminum and steel, said valve spool being slidableaxially within said bore between an axial position at which an outerfirst one of said valve elements is adjacent an end portion of said boreand the second and third ones of said valve elements are located instraddling position relative to both said adjacent juncture locationswhereby said inlet and outlet ducts are in cornmunication with eachother through a portion of said bore intermediate said second and thirdvalve elements and the end portion of said bore adjacent said outerfirst valve element is isolated by said first valve element from both ofsaid ducts, and another position in said bore at which an outer one ofsaid second and third valve elements is adjacent another end of saidbore and one of said second and third valve elements is positioned insaid bore intermediate said juncture locations, at which anotherposition said inlet and outlet ducts are thereby cut off fromcommunication with each other, and the other end portion of said boreadjacent said outer one of said second and third valve elements isisolated from both said ducts; and means for introducing fluid underpressure to one outer end surface of one of said outer valve elements tomove said valve spool axially in said bore between said positions.

8. Valve apparatus comprising: a valve body portion having a bore formedtherein; closure means for each end of said bore; separate inlet andoutlet ducts in said body, each communicating with an intermediateportion of said bore at separate adjacent longitudinally spacedapartjuncture locations, a valve spool located in said bore and slidableaxially therein, said valve spool having first, second and thirdcoaxial, axially spaced-apart, annular valve elements interconnected byintermediate stem portions of reduced outside diameter relative to thatof said valve elements, the peripheral surface of contact of each ofsaid valve elements, with the inside surface of the wall of said boreeach having a longitudinally convexly curved shape and having a maximumoutside diameter greater than the inside diameter of the said surface ofsaid bore, whereby said surface of contact and the inside surface ofsaid bore make an interference t with one another, said valvebody'portion and said annular valve elements being composed of amaterial having a hardness and rigidity at least approximating that of ametal of the class consisting of aluminum and steel, said valve spoolbeing positionable axially within said bore such that a first one ofsaid valve elements-is located adjacent an end portion of said bore andthe second and third ones of said valve elements are located in bridgingpositions relative to said adjacent juncture locations whereby saidinlet and outlet ducts are initially in communication with each otherthrough a portion of said bore intermediate said second and third valveelements and the end portion of said bore adjacent said first valveelement is isolated by said first valve element from said second valveelement and from both of said ducts, and positionable axially withinsaid bore such that one of said second and third valve elements ispositioned laxially within said bore intermediate said juncturelocations and said inlet and outlet ducts are thereby cut ot fromcommunication with cach other` and thc end portion of said liorcadjacent said third valve clement is isolated by said third valveelement from at least one of said ducts; and means including a quantityof ignitable, combustible gasgenerating material in at least one endportion of said bore; and means to ignite said combustible materialthereby to apply gas pressure to the outer end surface of one of saidvalve elements to move said valve spool axially in said bore betweensaid positions.

9. Valve apparatus in accordance with claim 6 and a restricted,'rpressure equalizing passage extending from one end portion to theopposite end portion of said bore.

10. Valve apparatus in accordance with claim 7 and a restricted,pressure equalizing passage extending from one end portion to theopposite end portion of said bore.

11. Apparatus in accordance with claim 1 in which said material is arigid metallic material.

References Cited in the file of this patent UNITED STATES PATENTS

1. VALVE APPARATUS COMPRISING: A VALVE BODY PORTION HAVING A BORE FORMEDTHEREIN; CLOSURE MEANS FOR EACH END OF SAID BORE; SEPARATE INLET ANDOUTLET DUCTS IN SAID BODY, EACH COMMUNICATING AT SEPARATE LONGITUDINALLYSPACEDAPART LOCATIONS, WITH SAID BORE, THERE BEING AN INTERMEDIATE,UNINTERRUPTED SECTION OF SAID BORE EXTENDING BETWEEN SUCH SPACED-APARTLOCATIONS; A VALVE ELEMENT LOCATED COAXIALLY IN SAID BORE, SAID VALVEELEMENT EXTENDING CLOSINGLY ACROSS SAID BORE AND HAVING A PERIPHERALSURFACE PORTION IN SLIDABLE SEALING ENGAGEMENT WITH THE INSIDE SURFACEOF THE WALL OF SAID BORE, SAID VALVE BODY PORTION AND SAID SURFACEPORTION BEING COMPOSED OF A MATERIAL HAVING A HARDNESS AND RIGIDITY ATLEAST APPROXIMATING THAT OF A METAL OF THE CLASS CONSISTING OF ALUMINUMAND STEEL, SAID PERIPHERAL SURFACE HAVING THE FORM OF A LONGITUDINALLYCONVEXLY CURVED ZONE AND SAID ZONE HAVING A MAXIMUM OUTSIDE DIAMETERGREATER THAN THE INSIDE DIAMETER OF SAID BORE, WHEREBY SAID PERIPHERALSURFACE MAKES AN INTERFERENCE PRESS FIT WITHIN SAID BORE, SAID VALVEELEMENT BEING SLIDABLE AXIALLY WITHIN SAID BORE BETWEEN AN AXIALPOSITION IN A SECTION OF SAID BORE OUTSIDE OF SAID INTERMEDIATE SECTIONAT WHICH SAID DUCTS ARE IN COMMUNICATION WITH EACH OTHER THROUGH SAIDINTERMEDIATE SECTION, AND AN AXIAL POSITION WITHIN SAID INTERMEDIATESECTION AT WHICH SAID DUCTS ARE THEREBY CUT OFF FROM COMMUNICATION WITHEACH OTHER, WHILE MAINTAINING SAID FIT IN SAID SECTION OF SAID BORE; ANDFORCE MEANS ACTUATABLE FOR MOVING SAID VALVE ELEMENT AXIALLY IN SAIDBORE BETWEEN SAID POSITIONS.